JPS6090765A - Bubble collector for ink jet head - Google Patents

Abstract

PURPOSE:To prevent the intrusion of air bubbles generated inan ink supply tube into the head by providing an air bubble trap and an ionization electrode to the ink supply tube of the ink jet head and also providing an air bubble collecting electrode to the air bubble trap. CONSTITUTION:An ionization electrode 4 is attached to the inside of a supply tube 5 through which ink is directed to the head 1 in such a way as to directly make it contact with ink, and a collecting electrode 2 is attached to the outside of an air bubble trap 3. The cross section of the tube 5 is made smaller in the ionization electrode 4 portion, thereby shortening the distance between the electrodes and also raising the pressures of the portion. A high frequency and high voltage is applied to the ionization electrode 4, and a DC voltage is applied to the collection electrode. Under the condition, air bubbles are made smaller in the ionization electrode portion of the supply tube and ionized by high-frequency and high voltage. The ionized air bubbles are divided into positive and negative ions and attracted by electric field of the collection electrode to collect the air bubbles.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to an inkjet printer.
This invention relates to a mechanism that prevents air bubbles from entering the head.

<Prior art> As shown in FIG. 5, a conventional device of this type has a head 1 having a pressure chamber 12 connected to a supply pipe 5, and a filter 11 attached to the inlet of the head 1 to remove air bubbles. structure was adopted. This structure had the problem that no matter how fine the filter mesh was, the gas particles were smaller, so air bubbles would pass through and the ink would no longer be ejected.

<Purpose> The purpose of the present invention is to prevent air bubbles generated in the supply pipe from entering the head.

The invention has two pairs of electrodes, one an ionizing electrode attached to a supply tube connected to the head inlet. This is an electrode for ionizing bubbles generated within the ink. The other is a collection electrode that is provided with a bubble reservoir attached in a direction different from the supply pipe and attached to this bubble reservoir. This electrode collects ionized air bubbles.

To explain this invention based on the drawings, in FIG.
The collecting electrode 2 is attached (or deposited) on the outside of the bubble reservoir.

The supply pipe 5 has a small cross-sectional area at the ionization electrode 4 portion. This allows i! The distance between the electrodes decreases, and the pressure in this area increases. A high frequency and a high voltage are applied to the ionization WL pole 4, and a DC voltage is applied to the collection electrode.

In the above situation, the bubbles become small at the ionization electrode part of the supply pipe, are ionized by high frequency and high voltage, and are separated into positive and negative ions, which are attracted and collected by the electric field of the collection electrode.

FIG. 2 is a sectional view taken along line A-A' in FIG.

3 and 4 show other embodiments taken along the A-A' cross section of FIG. 1. In FIG. 3, several electrodes 51 and 32 are arranged in parallel, and in FIG. The electrode 41 is provided inside the circumference of the supply tube, and the electrode 42 is provided at the center of the supply tube.This reduces the distance between the electrodes and facilitates ionization.

The collection electrode may also be similar to the embodiments shown in FIGS. 6 and 4.

As explained above, the present invention includes an ionization electrode that ionizes air bubbles in a supply pipe connected to the inlet of the henodor 1, and a collection 1 that collects the air bubbles. By providing the poles, air bubbles can be prevented from entering the head, and stable head operation can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a bubble collecting device for an inkjet head of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A' in FIG.
3 and 4 are cross-sectional views of other embodiments, and FIG. 5 is a vertical cross-sectional view of a conventional device. 1...Head having a pressure chamber 2...Collecting electrode 3...Bubble reservoir 4.31. 32,41. 42...Ionization electrode 5
... Supply pipe 12 ... Pressure chamber that applies pressure to ink using a piezo etc. Fig. 3 Fig. 4 Fig. 5

Claims (1)

[Claims] In an inkjet head that has a pressure chamber that applies pressure to the ink and prints by ejecting ink, there is a bubble reservoir connected to the supply pipe that supplies ink to the inkjet head, and a bubble reservoir that is attached to the supply pipe. an ionization electrode;
A bubble collection device for an inkjet head, comprising a collection electrode attached to a bubble reservoir, and collecting ionized bubbles in the bubble reservoir.